rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6953/1:b..l P5853/3:b..l
rcu: (detected by 1, t=10503 jiffies, g=18113, q=958327 ncpus=2)
task:syz-executor state:R running task stack:22808 pid:5853 tgid:5853 ppid:5852 task_flags:0x400100 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7145
preempt_schedule+0xae/0xc0 kernel/sched/core.c:7169
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__local_bh_enable_ip+0x13e/0x1c0 kernel/softirq.c:414
local_bh_enable include/linux/bottom_half.h:33 [inline]
rcu_read_unlock_bh include/linux/rcupdate.h:910 [inline]
__dev_queue_xmit+0x1d79/0x3b50 net/core/dev.c:4752
dev_queue_xmit include/linux/netdevice.h:3361 [inline]
neigh_hh_output include/net/neighbour.h:531 [inline]
neigh_output include/net/neighbour.h:545 [inline]
ip_finish_output2+0xd03/0x1160 net/ipv4/ip_output.c:235
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip_output+0x2a1/0x3c0 net/ipv4/ip_output.c:436
ip_local_out net/ipv4/ip_output.c:129 [inline]
__ip_queue_xmit+0x1106/0x1b00 net/ipv4/ip_output.c:532
__tcp_transmit_skb+0x2215/0x3680 net/ipv4/tcp_output.c:1479
tcp_transmit_skb net/ipv4/tcp_output.c:1497 [inline]
tcp_write_xmit+0x1862/0x67f0 net/ipv4/tcp_output.c:2833
__tcp_push_pending_frames+0x97/0x360 net/ipv4/tcp_output.c:3016
tcp_sendmsg_locked+0x4afd/0x5620 net/ipv4/tcp.c:1356
tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1393
sock_sendmsg_nosec net/socket.c:714 [inline]
__sock_sendmsg+0x19c/0x270 net/socket.c:729
sock_write_iter+0x258/0x330 net/socket.c:1179
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c6/0xb30 fs/read_write.c:686
ksys_write+0x145/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1f8898d620
RSP: 002b:00007ffe1c41ca98 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000002165b0b40 RCX: 00007f1f8898d620
RDX: 0000000000000360 RSI: 00007f1f847ffca0 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000007 R09: 00000000003ffde8
R10: 92b8c1adbd0ff381 R11: 0000000000000202 R12: 0000000000000360
R13: 00005555670f0950 R14: 00007ffe1c41cf60 R15: 00007f1f847ffca0
task:syz.0.236 state:R running task stack:26888 pid:6953 tgid:6951 ppid:5883 task_flags:0x40044c flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7145
preempt_schedule+0xae/0xc0 kernel/sched/core.c:7169
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
zap_pte_range mm/memory.c:1756 [inline]
zap_pmd_range mm/memory.c:1818 [inline]
zap_pud_range mm/memory.c:1847 [inline]
zap_p4d_range mm/memory.c:1868 [inline]
unmap_page_range+0x3a79/0x4370 mm/memory.c:1889
unmap_single_vma mm/memory.c:1932 [inline]
unmap_vmas+0x399/0x580 mm/memory.c:1976
exit_mmap+0x248/0xb50 mm/mmap.c:1280
__mmput+0x118/0x430 kernel/fork.c:1129
exit_mm+0x1da/0x2c0 kernel/exit.c:582
do_exit+0x648/0x2300 kernel/exit.c:949
do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
get_signal+0x1286/0x1340 kernel/signal.c:3034
arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe10b78eba9
RSP: 002b:00007fe1099d5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007fe10b9d6090 RCX: 00007fe10b78eba9
RDX: 0000200000000400 RSI: 000000004020ae46 RDI: 000000000000000d
RBP: 00007fe10b811e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe10b9d6128 R14: 00007fe10b9d6090 R15: 00007fe10baffa28
rcu: rcu_preempt kthread starved for 9081 jiffies! g18113 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:27160 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7058
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:__debug_check_no_obj_freed lib/debugobjects.c:1092 [inline]
RIP: 0010:debug_check_no_obj_freed+0x243/0x470 lib/debugobjects.c:1129
Code: 67 18 4c 89 e0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 4c 89 e7 e8 36 67 52 fd 49 8b 2c 24 48 3b 6c 24 50 <0f> 92 c0 49 39 ed 0f 96 c1 08 c1 75 8c 4d 8d 67 10 4c 89 e0 48 c1
RSP: 0018:ffffc900000070f0 EFLAGS: 00000087
RAX: 1ffff11007e6003b RBX: 0000000000000031 RCX: dffffc0000000000
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90000006fe0
RBP: ffff88803f301e50 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000000dfc R12: ffff88803f3001d8
R13: ffff888157e9c9b0 R14: 1ffff11007e60038 R15: ffff88803f3001c0
FS: 0000000000000000(0000) GS:ffff888125c15000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdb4124f5a3 CR3: 0000000075c14000 CR4: 00000000003526f0
Call Trace:
slab_free_hook mm/slub.c:2353 [inline]
slab_free mm/slub.c:4695 [inline]
kmem_cache_free+0x113/0x400 mm/slub.c:4797
nft_synproxy_eval_v4+0x376/0x560 net/netfilter/nft_synproxy.c:60
nft_synproxy_do_eval+0x345/0x570 net/netfilter/nft_synproxy.c:141
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
nft_do_chain+0x40c/0x1920 net/netfilter/nf_tables_core.c:285
nft_do_chain_inet+0x25d/0x340 net/netfilter/nft_chain_filter.c:161
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623
nf_hook include/linux/netfilter.h:273 [inline]
NF_HOOK+0x206/0x3a0 include/linux/netfilter.h:316
NF_HOOK+0x309/0x3a0 include/linux/netfilter.h:318
__netif_receive_skb_one_core net/core/dev.c:5991 [inline]
__netif_receive_skb+0x143/0x380 net/core/dev.c:6104
process_backlog+0x60e/0x14f0 net/core/dev.c:6456
__napi_poll+0xc7/0x360 net/core/dev.c:7506
napi_poll net/core/dev.c:7569 [inline]
net_rx_action+0x707/0xe30 net/core/dev.c:7696
handle_softirqs+0x283/0x870 kernel/softirq.c:579
__do_softirq kernel/softirq.c:613 [inline]
invoke_softirq kernel/softirq.c:453 [inline]
__irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: 53 e8 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d b3 e9 0d 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8de07d80 EFLAGS: 000002c2
RAX: 0129b4575920d200 RBX: ffffffff819693f8 RCX: 0129b4575920d200
RDX: 0000000000000001 RSI: ffffffff8d9b9e1e RDI: ffffffff8be33e80
RBP: ffffffff8de07eb8 R08: ffff8880b8632f9b R09: 1ffff110170c65f3
R10: dffffc0000000000 R11: ffffed10170c65f4 R12: ffffffff8fa3a530
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1bd2a20
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:757
default_idle_call+0x74/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:190 [inline]
do_idle+0x1e8/0x510 kernel/sched/idle.c:330
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
rest_init+0x2de/0x300 init/main.c:744
start_kernel+0x3a9/0x410 init/main.c:1097
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:307
x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:288
common_startup_64+0x13e/0x147